VBA400
VALVE BASS AMPLIFIER
WARNING! - Important safety instructions
To fully com plim ent the VBA400 we have produced two specially designed cabinets, the
8x10” VBC810 and the 4x12” VBC412 which com bine cool looks with classic Marshall tone.
!
WARNING: This apparatus must be earthed!
A
B
C
D
E
PLEASE read this instruction manual carefully before switching on.
ALWAYS use the supplied mains lead, if a replacement is required please contact your authorised Marshall Dealer.
NEVER attempt to by-pass the fuses or fit ones of the incorrect value.
In order to get the m ost from your VBA400 please read this handbook carefully before
plugging in.
DO NOT attempt to remove the amplifier chassis, there are no user serviceable parts.
VBA4 0 0 S e t -u p g u id e
Refer all servicing to qualified service personnel including replacement of fuses and valves. Servicing is required when the
apparatus has been damaged in any way, such as when the power supply cord or plug is damaged, liquid has been spilled or
objects have fallen into the apparatus, the apparatus has been exposed to rain or moisture, does not operate normally or has
been dropped.
CAUTION!: TO REDUCE THE RIS
WITH THE
UPPL CORD BEFORE CHANGING FUSE. TO REDUCE THE
RIS OF ELECTRIC HOCK DO NOT REMOVE COVER. NO USER ERVICEABLE
PARTS INSIDE. REFER ERVICING TO QUALIFIED ERVICE PERSONNEL.
K
OF FIRE REPLACE FUSES
DO NOT OBSTRUCT FAN EXIT
TUNER
EFFECTS LOOP
D.I. OUTPUT
S
AME TYPE AND RATING ONLY. DISCONNECT
!
S
Y
OUTPUT
K
S
S
2
Ohm
4
Ohm
LO
W
HIGH
MAINS INPUT
S
S
ATTENTION!: POUR EVITER LES RISQUES D’INCENDIE UTILISER UN
FUSIBLE DE MEME TYPE ET DE MEME CALIBRE. DEBRANCHER AVANT DE
REMPLACER LE FUSIBLE. POUR EVITER LES RISQUES DE DECHARGES
Made in England by:
ELECTRIQUES
AUCUNE PIECE
TOUJ OURS APPEL
,
NE PAS OUVRIR LE COUVERCLE. CET APPAREIL NE COMPORTE
USCEPTIBLE D’ETRE REPAREE PAR VOS OINS FAITES
UN TECHNICIEN QUALIFIE POUR TOUTE REPARATION.
VBA4 0 0
Marshall Amplification plc,
Bletchley, Milton Keynes,
England.
S
S
.
400 Watts RMS
Into 2/4 hms
IMPEDANCE
SELECTOR
FAN
SPEED
H.T.
FUSE
L.T.
FUSE
A
SEND
RETURN
O
WARNING!:
S
HOCK HAZARD. DO NOT OPEN. TO REDUCE THE RIS
K
OF FIRE OR ELECTRIC
NORMAL
S
HOCK DO NOT EXPOS
E
THIS EQUIPMENT TO RAIN OR MOISTURE. THIS APPARATUS MUS
T
BE EARTHED.
230V 50 Hz
~
LOUDSPEAKER OUTPUTS
T
10A
8A
4A
T
4A
4A
2A
100V
120V
230V
EARTH LIFT
900 Watts
T
T
T
AVIS!: RISQUE DE CHOC ELECTRIQUE. NE PAS OUVRIR. POUR EVITER LES RISQUES D’INCENDIE ET DE DECHARGES
ELECTRIQUES N’EXPOSEZ AMAIS CET APPAREIL ’HUMIDITE OU LA PLUIE. CONNECTER CET APPAREIL LA TERRE.
WARNING!: RISK OF HAZARDOUS ENERGY! AVIS!: ENERGIE ELECTRIQUE DANGEREUSE!
T
,
J
A
L
A
A
REFER TO MANUAL FOR FULL DETAILS. SE REFERER AU MANUEL POUR PLUS DE DETAILS.
F
NEVER use an amplifier in damp or wet conditions. No objects filled with liquids should be placed on the apparatus. When
cleaning, only use a dry cloth.
G
H
ALWAYS unplug this apparatus during lightning storms or when unused for long periods of time.
PROTECT the power cord from being walked on or pinched particularly at plugs, convenience receptacles and at the point where
they exit from the apparatus.
I
J
DO NOT switch the amplifier on without the loudspeaker connected.
ENSURE that any extension cabinets used are of the correct impedance.
Tu n e r
➲ EUROPE ONLY
- NOTE: This equipment has been tested and found to comply with the requirements of the EMC directive
(Environments E1, E2 and E3 EN 55103-1/2) and Low Voltage directive in the E.U.
➲ EUROPE ONLY - NOTE: The Peak Inrush current for the VBA400 is 204 amps.
Effe c t s P ro c e s s o r
Re c o rd in g o r P .A. Eq u ip m e n t
VBC4 1 2
VBC8 1 0
➲ CAUTION: Any changes or modifications not expressly approved by the party responsible for compliance may void the user’s
authority to operate the equipment.
VBA4 0 0 Fro n t P a n e l Fe a t u re s (p a g e 2 6 )
➲ NOTE: It is recommended that all audio cables used, with the exception of the speaker lead, to connect to the VBA400 are of a high
quality screened type. These should not exceed 10 metres in length. Always use a non-screened Marshall approved speaker lead with
the VBA400 Head and extension cabinets.
1. Power Switch
5. Bright
➲ WARNING: Do not obstruct ventilation grilles and always ensure free movement of air around the amplifier!
Controls mains power to the amplifier,
activating the valve heaters and other auxiliary
circuits including the fan. This should be
switched on before the standby switch.
The Bright switch adds high frequency presence,
giving top end brilliance, crispness and bite to
your sound.
USA ONLY - DO NOT defeat the purpose of the polarised or grounding type plug. A polarised plug has two blades with one
wider than the other. A grounding type plug has two blades and a third grounding prong. The wide blade or the third prong is
provided for your safety. When the provided plug does not fit into your outlet, consult an electrician for replacement of the
obsolete outlet.
6. Treble
Follow all instructions and heed all warnings - KEEP THESE INSTRUCTIONS !
2. Standby Switch
Controls the high frequencies of the bass guitar
tone, making your sound brighter when
increased.
Controls the H.T. (high tension) supply to the
valves to allow them to attain the correct
working temperature before playing. To prolong
the life of the valves it is always advisable to
switch on the Mains Power Switch (item 1)
about 2 minutes before switching on the Standby
(item 2).
Constant exposure to the high sound pressure levels of which this amplification system is capable could
result in permanent damage to your hearing.
Although individuals will vary in their susceptibility to noise induced hearing loss, almost everyone will
have their hearing impaired if exposed to intense sound levels for a sufficient length of time.
To prevent the occurance of permanent hearing loss, it is advisable to wear ear plugs or protectors if you
are going to be exposed to high noise levels for prolonged periods.
7. Middle
Dictates the middle register of the amplifier.
Turning this up will make your bass sound
fatter. Conversely reducing the amount of
middle in your tone will result in a sharper
sound.
This procedure allows the valves to heat up fully
before use. On switching off, the Standby
should always be switched before the Power
Switch.
In t ro d u c t io n
8. Contour
VBA stands for Valve Bass Am plifier and who better to m ake a bass am p powered by valve
technology than Marshall Am plification? Over 36 years of designing and m anufacturing world
renowned high quality valve am ps has given us priceless knowledge, experience and insight in
the world of valve tone.
3 position control adjusting the overall tonal
voicing of the amplifier. Position 1 tailors the
response of the amplifier for smooth low end,
restrained lower mids, and mild high end lift, to
give the classic vintage valve bass tone. In
position 2 the lower mid is made more
prominent whilst simultaneously the upper mids
are subtly scooped to give a more aggressive,
growling quality to the amplifier’s tone.
The standby facility is particularly useful live,
between sets, as it allows you to reduce the
amount of heat generated by the amplifier but
keep the valves operating, which is conducive to
longevity of valve life. Valve life can be further
increased by always ensuring that the amplifier
is allowed to cool down completely after use and
before transportation.
The VBA400 gives you 400 Watts of Marshall valve power courtesy of 12 valves; 8 6550 power
valves, 3 ECC83 classic Marshall pre-am p valves and 1 ECC82 valve.
In addition to great tone, the VBA400 com bines a num ber of other exciting and useful features.
Situated on the rear panel of the am p is a Tuner Output which allows you to keep a tuner in line
at all tim es (the bass is still plugged into the input on the front panel). Should you want to tune
up during a live situation in silence, sim ply press the Tuner Mute facility button and both the
sound to your speakers and to the DI will be cut off.
Position 3 introduces a gentle overall mid boost
for an immediate, cutting, ‘in your face’ tone.
3. Master Volum e
Governs the overall volume of the VBA400.
9. Bass
All valve am ps need to be connected to a speaker before use and failure to do so will result in
serious dam age to the am p. To ensure that you do not dam age your VBA400 by inadvertently
forgetting to plug your am p into a speaker, we have designed the unit so that power cannot be
applied internally unless it is connected to a speaker.
4. Deep
Controls the amount of low frequencies or
bottom end in your tone.
The Deep Switch adds a tuned or resonant bass
boost to your sound, increasing bottom end thud,
without making your tone woolly around the
bottom end.
The VBA400 also features an instant overall tonal re-shaper in the form of a Contour control
which has three pre-sets to allow you to dial in three different characters in an instant.
2
3
may give you the sound that you are trying to
capture.
To ensure optimum cooling of the amplifier in
all operating environments, the fan has two
operating speeds, low and high. Low should be
selected for normal operating situations.
However, if this amplifier is going to be used in
close proximity to other units generating
appreciable amounts of heat, or if the ambient
air temperature is high, the higher fan speed
should be selected. The VBA400 features over
temperature protection which will shut the unit
down should internal temperatures become
excessive, due for example to obstructed front or
rear air vents. This protection is self-resetting
after a period of approximately thirty minutes.
10. Gain
5. D.I. output
The VBA400 is an all valve bass head and as
The VBA400 features a low impedance,
balanced XLR D.I. Output for connection to
professional recording or P.A. equipment.
such is ideally suited to creating thick musically
overdriven tones or warm clean tones. If you
require a clean bass sound turn this control up
until your bass just starts to distort and then back
it off slightly. If on the other hand you would
like a distorted sound, simply turn up the Gain
control until the required amount of distortion is
achieved. Another tip, for those of you who
have got active basses who want a distorted
tone, is to try plugging your bass into the Passive
Input. This will cause no harm and may provide
the sound you are looking for.
If you are using a Tuner in-line via item 1 on the
rear panel, you should still use one of these
inputs to connect your bass.
See Item 15 on front panel for more details.
13. Passive
6. Im pedance Selector
This input is designed to take the signal from a
passive bass. If your bass guitar is passive plug
it in here. We recommend that you always use a
high quality screened cable for this to help
prevent noise, interference and unwanted
feedback.
It is imperative that the output impedance
selector on this amplifier matches the impedance
of the speaker(s) that it is driving.
The VBA400 delivers 400 Watts R.M.S. into 2
or 4 Ohms. Both the VBC810 and VBC412
cabinets are 4 Ohm cabinets. Therefore if you
are using one cabinet ensure that the impedance
selector is set to 4 Ohms, and if you are using 2
cabinets ensure that the impedance selector is set
to 2 Ohms.
14. Active
10. H.T. Fuse
Tuner Mute
This input is designed to take the signal from an
active bass. If your bass guitar is active plug it
in here. Again we recommend that you always
use a high quality screened cable to help prevent
noise, interference and unwanted feedback.
Always ensure that the correct value fuse is
fitted - see rear panel for details.
The VBA400 features a Tuner Mute facility. On
the rear panel there is a tuner output, item 1,
which allows you to keep a tuner connected
permanently in-line. By pressing the Tuner
Mute On/Off button, item 12 on the front panel,
you will cut the sound to the speakers and to the
DI output allowing you to tune up in silence.
If this fuse fails repeatedly, you should refer the
amplifier to a qualified Marshall service agent.
Failure to do this can result in serious damage to
the amplifier.
11. L.T. Fuse
15. D.I. pre-post selector
7. & 8. Loudspeaker Outputs
Always ensure that the correct value fuse is
fitted - see rear panel for details.
The VBA 400 features a D.I. Output, item 5 on
the rear panel, designed for connection to
professional recording or P.A. equipment.
For connection to VBC810 and or VBC412
cabinets. See above for impedance details.
11. LED
If this fuse fails repeatedly, you must refer the
amplifier to a qualified Marshall service agent.
Indicates when the Tuner Mute facility is in use.
Always use short, high quality, heavy duty
speaker leads to connect this amplifier to the
loudspeaker cabinets. Two speaker leads are
supplied with the amplifier for this purpose.
Do not use screened, guitar type, leads.
By selecting ‘Pre’, the signal for the DI will be
taken from a point in the signal path before the
front panel controls and will only be affected by
the Tuner Mute, Item 12. This means that you
will have no other influence over your sound
being sent to the external recording or P.A.
equipment connected to the D.I. output socket.
By selecting ‘Post’, the signal for the DI will be
taken after the Gain and Equalisation controls
(but before the master volume control), giving
you tonal and level control over the signal being
sent to the external equipment.
12. On/Off
12. Mains Input
Allows you to switch the Tuner Mute facility on
and off.
Connects the amplifier to the mains power
supply.
Inputs
9. Fan Speed - Low & High
The VBA400 is able to operate on 100, 115 or
230 Volts A.C. (50-60 cycles) by appropriate
selection of internal voltage setting links and
fuse types. Should you require to operate your
VBA400 at a different mains voltage to that
which the unit was originally intended, refer the
amplifier to a qualified Marshall service agent,
who will make the required adjustments.
Though the Passive and Active inputs were
designed around the signal from an active bass
and a passive bass guitar respectively, you
should experiment to see which input best suits
your style. Don’t worry, connecting your bass to
the wrong input will not harm your VBA400 but
The VBA400 features 12 valves in total, 8 of
which are power valves. Normal air convection
would not be sufficient to keep such an amplifier
cool, and the VBA400 therefore features a fan
which sucks cool air through the front vent and
pushes the resulting warm air out through the
rear vent.
VBA4 0 0 Re a r P a n e l Fe a t u re s (p a g e 2 6 )
Va lve Re p la c e m e n t
1. Tuner Output
3. Return
The valves fitted at the Marshall factory have been extensively tested and selected to ensure close
matching of electrical characteristics, which, in conjunction with the amplifier’s internal bias and balance
controls (which are not user adjustable) should ensure long and reliable operating life.
The Tuner Output allows you to keep a tuner in-
line at all times. See Tuner Mute in the Front
panel Functions section for a full overview of
this facility.
For connection to the output of an external
effects processor.
4. D.I. Norm al / Earth Lift
As with any valve amplifier, the valves (particularly the output valves) do not have an infinite life and will
require replacement at some point. The life expectancy of a set of valves depends on many factors including
how frequently the amplifier is used, the quality of the valves fitted and proper use of the mains and standby
switches when powering the amplifier up and down.
Linking one piece of earthed electrical
equipment to another earthed piece of electrical
equipment can result in an audible hum, due to
the formation of an earth loop. In the past
people would get round this problem by
removing the earth of one of the appliances,
which is of course extremely dangerous. The
VBA400 features an Earth Lift which allows
you to safely ‘lift’ the D.I. signal earth on the
amp, should you be experiencing earth loop hum
problems.
Effects Loop
The VBA400 features a series effects loop for
optimum connection of external effects. As this
is a series loop, all of the pre-amp signal is
passed through the loop when in operation and
the blend between ‘dry’ and ‘effects’ is
determined solely by the setting of the ‘mix’
facility on your chosen effects processor.
Signs that the valves are nearing the end of their useful operating life include loss of perceived output
power, increase in valve microphony (detectable as a background ‘ringing’ type noise) and deterioration in
tone. When the time comes to fit new valves it is strongly recommended that only Marshall replacement
valves, tested to the same specification as the originals, be used, and that these are installed by an approved
Marshall service agent who has access to the measuring equipment required to set the internal bias and
balance controls to optimally suit the new valves being fitted.
2. Send
For connection to the input of an external effects
processor.
4
5
VBA400 Front Panel
OUTPUT CONTROL
EQUALISATION
INPUT
D.I.
2
1
OFF
OFF
ON
3
VBA400
VALVE BASS AMPLIFIER
DEEP BRIGHT
PRE
POST
MUTED ON/OFF
ON
0
10
0
10
0
10
0
10
BASS
0
10
GAIN
TUNER
MUTE
CONTOUR
SELECT
POWER
STANDBY
MASTER VOLUME
TREBLE
MIDDLE
PASSIVE
ACTIVE
12
1
2
3
4
5
6
7
8
9
10
11
13
14
15
7
8
10 11
12
VBA400 Rear Panel
CAUTION!: TO REDUCE THE RISK OF FIRE REPLACE FUSES
WITH THE SAME TYPE AND RATING ONLY. DISCONNECT
SUPPLY CORD BEFORE CHANGING FUSE. TO REDUCE THE
RISK OF ELECTRIC SHOCK DO NOT REMOVE COVER. NO USER SERVICEABLE
PARTS INSIDE. REFER SERVICING TO QUALIFIED SERVICE PERSONNEL.
DO NOT OBSTRUCT FAN EXIT
TUNER
OUTPUT
EFFECTS LOOP
D.I. OUTPUT
!
2 Ohm 4 Ohm
LOW HIGH
MAINS INPUT
ATTENTION!: POUR EVITER LES RISQUES D’INCENDIE UTILISER UN
FUSIBLE DE MEME TYPE ET DE MEME CALIBRE. DEBRANCHER AVANT DE
REMPLACER LE FUSIBLE. POUR EVITER LES RISQUES DE DECHARGES
ELECTRIQUES, NE PAS OUVRIR LE COUVERCLE. CET APPAREIL NE COMPORTE
AUCUNE PIECE SUSCEPTIBLE D’ETRE REPAREE PAR VOS SOINS. FAITES
TOUJ OURS APPEL A UN TECHNICIEN QUALIFIE POUR TOUTE REPARATION.
Made in England by:
Marshall Amplification plc,
Bletchley, Milton Keynes,
England.
400 Watts RMS
Into 2/4 Ohms
IMPEDANCE
SELECTOR
FAN
SPEED
H.T.
FUSE
T10A
T8A
T4A
L.T.
FUSE
T4A
T4A
T2A
SEND
RETURN
WARNING!: SHOCK HAZARD. DO NOT OPEN. TO REDUCE THE RISK OF FIRE OR ELECTRIC
NORMAL
EARTH LIFT
230V ~ 50 Hz
900 Watts
SHOCK DO NOT EXPOSE THIS EQUIPMENT TO RAIN OR MOISTURE. THIS APPARATUS MUST BE EARTHED
LOUDSPEAKER OUTPUTS
100V
120V
230V
AVIS!: RISQUE DE CHOC ELECTRIQUE. NE PAS OUVRIR. POUR EVITER LES RISQUES D’INCENDIE ET DE DECHARGES
LA PLUIE. CONNECTER CET APPAREIL A LA TERRE.
WARNING!: RISK OF HAZARDOUS ENERGY! AVIS!: ENERGIE ELECTRIQUE DANGEREUSE!
ELECTRIQUES, N’EXPOSEZ J AMAIS CET APPAREIL A L’HUMIDITE OU
A
REFER TO MANUAL FOR FULL DETAILS. SE REFERER AU MANUEL POUR PLUS DE DETAILS.
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